Biomedical subjects

R D Pollak

Publications and source records attributed to R D Pollak.

11 recordsLinked to original sources

PubMed2000

Ethnic differences in the frequency of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in healthy Israeli populations.

Hyperhomocysteinemia is an independent risk factor for arteriosclerotic vascular disease. It can result from deficiencies of co-factors required for homocysteine metabolism and/or from genetic disorders of its metabolism. The association between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular disease is controversial, and may be affected by ethnic origin. A unique feature of the Israeli population is its ethnic diversity. The aim of this study was to study the frequency of the C677T MTHFR mutation in healthy Israeli ethnic groups. The frequency of the mutation was determined in 897 young healthy Jewish and Muslim Arab Israelis of eight different ethnic groups. Marked ethnic differences in the frequency of mutant homozygotes were found, ranging from 2% in Yemenite Jews, 4% in Sephardic Jews, 9% in Oriental Jews, 10% in Muslim Arabs, 16% in North African Jews, and 19% in Ashkenazi Jews. The frequency of mutant homozygotes was significantly higher in Ashkenazi Jews compared to Yemenites Oriental Jews, Sephardic Jews, and Muslim Arabs (chi2 = 12.35p < 0.001, chi2 = 8.17p = 0.004, chi2 = 6.04p = 0.01, chi2 = 6.54 p = 0.01, respectively). Our findings demonstrate the need for matching ethnic background in patients and controls when studying the association between the C677T MTHFR mutation and any disease.

Adolescent↗

PubMed2000

The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular dementia.

OBJECTIVE: To determine the association between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular dementia in Ashkenazi and non-Ashkenazi Jews. DESIGN: A case-control study. SETTING: Nursing homes in Jerusalem, Israel. PARTICIPANTS: Two hundred fifty nine Jewish people of Ashkenazi and non-Ashkenazi origin, older than age 70, who have vascular dementia (VD) (n = 85), Alzheimer's disease (AD) (n = 92), and who are cognitively intact (n = 82) with no clinical evidence of atherosclerotic vascular disease. MEASUREMENTS: The frequencies of the mutant allele (T allele) and homozygotes for the C677T MTHFR mutation (T/T genotype). The total plasma homocysteine (tHCT) level in 75 subjects. RESULTS: There were no significant differences in the frequencies of the T/T genotype or T allele among VD, AD, and cognitively intact older people of the same ethnic origin (0.15, 0.19, 0.25 T/T genotype and 0.42, 0.46, 0.47 T allele in Ashkenazi; 0.08, 0.06, 0.10 T/T genotype and 0.28, 0.32, 0.33 T allele in non-Ashkenazi with VD and AD, and in cognitively intact older people, respectively). The relative risk of VD associated with the T/T genotype versus the C/C genotype was 0.62 (95% CI, 0.19-1.19) in Ashkenazi and 0.65 (95% CI, 0.11-3.7) in non-Ashkenazi, respectively. The relative risk of AD associated with the T/T genotype was 0.85 (95% CI, 0.29-2.45) in Ashkenazi and 0.62 (95% CI, 0.1-4.3) in non-Ashkenazi, respectively. The frequencies of mutant homozygotes and allele were significantly higher in Ashkenazi than in non-Ashkenazi Jews (19.9% vs 7.5% T/T genotype, chi2 = 6.2, P = .01, 0.45 vs 0.31 T allele, chi2 = 9.77, P = .002 in Ashkenazi vs non-Ashkenazi, respectively). There were no differences in mean tHCT concentration among VD, AD, and cognitively intact older people. CONCLUSIONS: The MTHFR C677T is not associated with an increased risk of vascular dementia or Alzheimer's disease. The frequency of the mutation is significantly higher in Ashkenazi compared with non-Ashkenazi Jews.

Aged↗

PubMed2000

Orthopaedic manifestations of familial dysautonomia. A review of one hundred and thirty-six patients.

BACKGROUND: Familial dysautonomia is a hereditary multisystemic disease primarily affecting people of Ashkenazi Jewish descent. Musculoskeletal problems are related to gait disorders, spinal deformities, foot deformities, fractures, and arthropathies. METHODS: The charts and radiographs of 136 patients who ranged in age from three months to forty-six years (mean, sixteen years) were reviewed. Sixty-four patients were available for follow-up examination. RESULTS: Spinal deformity was the most common orthopaedic problem and was diagnosed in seventy-eight patients starting at the age of four years, with a prevalence of 86 percent (forty-eight of fifty-six) by the age of fifteen years. Forty-one (53 percent) of the seventy-eight patients had scoliosis only, thirty-four (44 percent) had kyphoscoliosis, and three (4 percent) had kyphosis only. Bracing was accompanied by emotional, pulmonary, and skin problems, leading to a high rate of noncompliance and progression of the curve. Twenty-four patients had an operation at a mean age of thirteen years (range, five to eighteen years): twenty patients had posterior spinal arthrodesis, and four had combined anterior and posterior arthrodesis. Fifteen patients had a total of nineteen complications, of which seven were systemic and twelve were related to the spinal fixation. Eight patients had revision surgery. At the time of the surgery, scoliosis was corrected from a mean of 55 degrees to a mean of 35 degrees and kyphosis was corrected from a mean of 69 degrees to a mean of 61 degrees. After a mean duration of follow-up of sixty-five months, scoliosis measured 49 degrees (range, 18 to 62 degrees) and kyphosis measured 67 degrees (range, 30 to 115 degrees). Postoperative progression of the deformity was caused by failure of the instrumentation or progression in unfused segments. Walking was delayed in 72 percent (ninety-four) of the 130 patients who were of walking age. All sixty-four of the patients who were examined had an ataxic gait. Foot deformities were found in sixteen patients, six of whom were treated surgically. Two patients had Charcot joints. Fifty-five patients sustained at least one fracture before skeletal maturity, with a mean of 1.5 fractures per patient. All but one of the fractures was treated nonoperatively, and fracture-healing was often accompanied by profuse callus formation. CONCLUSIONS: Spinal deformity is common in patients with familial dysautonomia. Bracing is of questionable benefit, and surgical intervention should be considered once curve progression is well documented. Arthrodesis should be extended as far proximally as possible to prevent junctional kyphosis. Swelling and warmth in a limb should raise suspicion of an undiagnosed fracture.

Adolescent↗

PubMed1998

Femoral neck osteopenia in patients with inflammatory bowel disease.

OBJECTIVE: The mechanism of bone loss in patients with inflammatory bowel disease (IBD) is not completely understood. The aim of this study was to assess indices of bone turnover and bone mineral density (BMD) in the lumbar spine and femoral neck in IBD patients. METHODS: Sixty-three patients with Crohn's disease and 41 with ulcerative colitis were studied. Serum bone-specific alkaline phosphatase (B-ALP), osteocalcin, parathyroid hormone (PTH), 25 hydroxyvitamin D, interleukin-6 (IL-6), and urinary N-telopeptide cross linked type 1 collagen (NTX) were determined. BMD of the lumbar spine and femoral neck was determined by dual x-ray absorptiometry in 59 patients. RESULTS: In the femoral neck 42% of the patients had osteopenia (-2.5 SD < BMD T score < -1 SD) and another 41% had osteoporosis (BMD T score < -2.5). In the spine 34% of the patients had osteopenia and additional 42% had osteoporosis. BMD T scores were lower in the femoral neck compared to the spine. Reduced BMD was unrelated to gender, disease type, lifetime corticosteroid dose, but inversely correlated with disease duration (r = -0.36, p < 0.05). Serum IL-6 was higher in IBD patients compared to controls. A reduced level of osteocalcin, a marker of bone formation, was present in 7% of patients and an increase in NTX, a marker of bone resorption, in 25% of them. Osteoporotic IBD patients (spine or hip BMD T score < -2.5) had increased serum IL-6, osteocalcin and PTH level compared to nonosteoporotic patients. CONCLUSIONS: There is a high prevalence of reduced BMD at the spine and femoral neck in IBD patients, which is more severe in the hip. Bone turnover in osteoporotic IBD patients is associated with an increase in osteocalcin, PTH and IL-6. IL-6 may play a role in the pathogenesis of bone loss in IBD.

Adult↗

PubMed1976